In general, secondary batteries refer to chargeable and dischargeable batteries, unlike primary batteries that are not chargeable. Such a secondary battery is being widely used in the high-tech electronic fields such as mobile phones, notebook computers, and camcorders.
Such a secondary battery according to the related art comprises an electrode assembly. Here, a positive electrode and a negative electrode are respectively disposed on top and bottom surfaces of a separator and then laminated by using a pressure and folded to manufacture the electrode assembly.
However, in the electrode assembly, the positive electrode has adhesion force greater than that of the negative electrode. Thus, if the positive electrode and the negative electrode adhere to the separator under the same condition, a deviation in adhesion force of the positive electrode and the negative electrode may occur. As a result, it is difficult to manufacture electrode assemblies having uniform quality.